U.S. patent application number 10/000163 was filed with the patent office on 2003-06-05 for apparatus and methods for prevention of age-related macular degeneration and other eye diseases.
Invention is credited to Lin, J.T..
Application Number | 20030105456 10/000163 |
Document ID | / |
Family ID | 21690211 |
Filed Date | 2003-06-05 |
United States Patent
Application |
20030105456 |
Kind Code |
A1 |
Lin, J.T. |
June 5, 2003 |
Apparatus and methods for prevention of age-related macular
degeneration and other eye diseases
Abstract
Surgical apparatus and surgical methods are proposed for the
prevention of age-related macular degeneration (AMD) and choroidal
neovascularization (CNV), and other eye diseases such as glaucoma
by removal of the sclera tissue to reduce its rigidity and increase
the flood flow and decrease pressure in the choriocapillaris. The
disclosed preferred embodiments of the system consists of a tissue
ablation means and a control means of ablation patterns and a fiber
delivery unit. The basic laser beam includes UV lasers and infrared
lasers having wavelength ranges of (0.15-0.36) microns and
(0.5-3.2) microns and diode lasers of about 0.98, 1.5 and 1.9
microns. AMD and CNV are prevented, delayed or reversed by using an
ablative laser to ablate the sclera tissue in a predetermined
patterns outside the limbus to increase the elasticity of the
sclera tissue surrounding the eye globe The surgery apparatus also
includes non-laser device of radio frequency wave, electrode
device, bipolar device and plasma assisted device
Inventors: |
Lin, J.T.; (Oviedo,
FL) |
Correspondence
Address: |
J.T. LIN
4532 Old Carriage Trail
Oviedo
FL
32765
US
|
Family ID: |
21690211 |
Appl. No.: |
10/000163 |
Filed: |
December 4, 2001 |
Current U.S.
Class: |
606/5 ; 606/10;
606/3 |
Current CPC
Class: |
A61F 2009/00865
20130101; A61F 9/008 20130101; A61F 9/00821 20130101; A61F 9/00802
20130101; A61F 2009/00891 20130101; A61B 2018/20359 20170501; A61F
2009/00897 20130101; A61F 2009/00863 20130101; A61B 18/14 20130101;
A61B 2018/20351 20170501 |
Class at
Publication: |
606/5 ; 606/3;
606/10 |
International
Class: |
A61B 018/18 |
Claims
I claim:
1. A surgery method of preventing age-related macular degeneration
(AMD) by reducing the rigidity of the sclera of an eye, whereby a
removal means is used to remove portion of the sclera tissue in a
predetermined pattern to reduce the risk factors of AMD selected
from the group consisting of low blood flow and high pressure in
the choriocapillaris and formation of drusen in the suretinal
space.
2. A surgical method as claimed in claim 1, wherein said removal
means includes a laser having a preferable wavelength of about
(0.15-3.2) microns.
3. A surgical method as claimed in claim 1, wherein said removal
means includes a physical blades.
4. A surgical method as claimed in claim 1, wherein said removal
means includes an electromagnetic wave at radio frequency, or
electrode device, or bipolar device or plasma assisted electrode
device.
5. A surgery method of preventing AMD in accordance with claim 1,
in which said predetermined pattern includes patterns selected from
the group consisting of radial lines, curved lines, ring-dot and
non-specific patterns around the area of the eye outside the
limbus.
6. A surgery method of preventing AMD in accordance with claim 1,
in which said rigidity of the sclera is reduced by the filling
effects of the sub-conjunctival tissue.
7 A surgical apparatus to remove a portion of the sclera tissue of
an eye comprising (a) a tissue removal means, and (b) a control
means of predetermined ablation pattern, whereby AMD can be
prevented by reducing the rigidity of the sclera.
8. A surgical apparatus as claimed in claim 7, wherein said removal
means included a laser having a wavelength range of about
(0.15-0.36) microns.
9. A surgical apparatus as claimed in claim 7, wherein said removal
means included infrared laser having a wavelength range of about
(0.8-3.2) microns.
10. A surgical apparatus as claimed in claim 8, wherein said laser
is selected from the group consisting of ArF excimer laser, XeCl
excimer laser, harmonic generation from Nd:YAG laser and Nd:YLF
laser.
11. A surgical apparatus as claimed in claim 9, wherein said
infrared laser is an optically pumped Erbium:YAG laser having a
wavelength of about 2.9 microns
12. A surgical apparatus as claimed in claim 9, wherein said
infrared laser is a solid-state short pulse laser having a
wavelength range of about (1.0-1.3) microns and a pulse duration
shorter than 10 nanoseconds.
13. A surgical apparatus as claimed in claim 9, wherein said
infrared laser is a semiconductor diode laser having a wavelength
range of about (0 8-2.1) microns
14. A surgical apparatus as claimed in claim 7, wherein said
control means is selected from the group consisting of a scanning
device having motorized reflection mirror, a refractive optics and
optical device
15 A surgical apparatus as claimed in claim 7, wherein said control
means includes the use of a fiber delivery unit to deliver said
laser in a predetermined pattern onto a plurality of positions on
the eye.
16. The apparatus of claim 15, wherein said fiber delivery unit is
operated by a mode selected the group consisting of contact-mode
and non-contact mode to ablate the sclera tissue.
17. A surgical apparatus as claimed in claim 15, wherein said fiber
delivery unit is controlled by the surgeon to perform a
predetermined patterns outside the limbus of the eye by manually
moving said fiber delivery unit.
18. A surgical apparatus as claimed in claim 7, wherein said
predetermined pattern is selected from the group consisting of
radial lines, curved lines, ring-dot and non-specific pattern
around the area outside the limbus.
19. A surgical apparatus as claimed in claim 7, wherein said
removal means includes a physical blades.
20. A surgical apparatus as claimed in claim 7, wherein said
removal means is selected from the group consisting of
electromagnetic wave at radio frequency, electrode device, bipolar
device oand plasma assisted electrode device.
21. A surgical apparatus to remove a portion of the sclera tissue
of an eye comprising: (c) a tissue ablation means, and (d) a
control means of predetermined ablation pattern, whereby glaucoma
can be prevented or treated by decreasing the intraocular pressure
of the treated eye.
22. A surgical apparatus as claimed in claim 21, wherein said
tissue ablation means includes a laser having a wavelength range of
about (0.15-3.2) microns.
23. A surgical apparatus as claimed in claim 21, wherein said
tissue ablation means is selected from the group consisting of a
physical blades, an electromagnetic wave at radio frequency,
oelectrode device, bipolar device and plasma assisted electrode
device.
24. A surgical apparatus as claimed in claim 21, wherein said
predetermined pattern is selected from the group consisting of
radial lines, curved lines, ring-dot and non-specific pattern
around the area outside the limbus.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to methods and apparatus for
the prevention of age-related macular degeneration and other eye
diseases.
[0003] 2. Background and Prior Art
[0004] Age-related macular degeneration (AMD) is the leading cause
of central visual loss in patients older than 50 years of age in
the United States. The 10% of patients with wet degeneration
accounts for 90% of the patients with severe vision loss to 20/200
or worse. The majority of eyes suffer severe visual loss of a
result of Choroidal neovascularization (CNV), which is the
formation of new blood vessels either between the retinal pigment
epithelium and Bruch membrance or the subretinal space.
[0005] CNV is a common manifestation of a variety of macular
diseases and can result in severe vision loss. Typically, CNV
complicates AMD, but it also can be seen in pathologic myopia,
ocular histoplasmosis, angioid streaks, and ocular inflammatory
diseases, and as an idiopathic condition. See Atlas of Ophthalmic
Surgery, Chapt. 8, ed. by N. Jaffe, (Mosby-Wolfe, 1996).
[0006] Recently, there has been an explosion of treatment options,
including the use of photodynamic therapy with verteporfin,
radiation, transpupillary thermotherapy, and feeder vessel
photo-coagulation and surgical techniques such as submacular
surgery and macular translocation. See J. Paerlman et al,
Contemporary Opthalmology, November 2001 (Lippincott Williams &
Wilkins, MD).
[0007] The proven effective treatment for AMD is laser
photocoagulation (LPD). However, it was reported that treatment of
well-defined subfoveal CNV was beneficial, but most patients
experienced an immediate decline in vision because of damage to the
overlying neurosensory retina. Freund et al demonstrated that only
13% of patients with CNV from AMD are eligible for treatment by
LPD. (See Freund K B, Am. J Ophthalmol 1993; vol. 115, pp. 786-91).
Therefore "prevention" of AMD is more important than cure it. The
present invention shall proposed methods for the prevention,
delaying or reversal of AMD. Before introducing these methods, we
shall review the background of the risk factors causing AMD as
follows.
[0008] The pathogenesis of AMD is not entirely known, but defects
in Bruch's membrane are associated with at least some forms of CNV
and are seen histologically in cases for which clinical-pathologic
correlation is available. The presence of the abnormal vessels,
combined with the development of subretinal transudates and
hemorrhage, ultimately results in irreparable damage to the
overlying neurosensory retina and permanent loss of vision.
[0009] The vascular model proposed by E. Friedman (Am J Ophthalmol
vol. 130, pp. 658-663 2000) stated that AMD is the result of the
accumulation of lipid in the sclera and in Bruch Membrance,
progressively increasing the stiffness of these tissues and
increasing the postcapillary resistance of the choroidal
vasculature, situated between the progressively noncompliant sclera
and noncompressable contents of the globe. This model also stated
that in addition to decreasing choroidal blood flow, the increase
in resistance or elevation the hydrostatic pressure of the
choriocapillaris, enhancing leakage and deposition of extracellular
proteins and lipids. In AMD, the location of the lipid deposition
is also a function of the intravascular hydrostatic pressure. The
lipids deposited in the sclera may originate in scleral vessels or
they may reach the sclera from the choroids by diffusion or
filtration down the transsclera hydrostatic pressure gradient.
[0010] In addition to the above risk factors of AMD and CNV, it was
also reported that hyperopia is frequently identified as a risk
factor for AMD in large case-control epidemiological studies. (See
Tang et al, German J Opthalmol 1993, vol. 2, pp.10-13). The
vascular model of Freidman suggested that this can be attributed to
the increased scleral rigidity associated with hyperopia. The
present inventor proposes that scleral rigidity should cause
"presbyopia" rather than "hyperopia". In Lin's U.S. Pat. No.
6,258,082, the present inventor proposed that presbyopia may be
reversed by a laser treatment which increases the elasticity of the
sclear-ciliary-zonule complex, where presbyopic patients are
treated by increasing their near vision accommodation. In the
present invention, we propose to use the mechanism based on an
"elastic theory" for the new application of prevention, delay or
reversal of AMD (or CNV) by reducing their risk factors which
includes choriodal low blood flow and the choriocapillaris high
pressure.
[0011] We proposed that the laser ablated sclera tissue "gap" may
be filled in by the sub-conjunctival tissue within few days after
the surgery. This filled in sub-conjunctival tissue is much more
elastic than the original sclera tissue and therefore cause the
scleral tissue surrounding the eye globe to become more elastic or
less rigid. This "elastic" mechanism shall then lower or eliminate
the risks factors causing AMD, namely the low blood flow in the
choriod and high hydrostatic pressure. Formation of lipids, drusen
and neovascularization localized in the periphery of the fundus may
be prevented, reduced or even reversed after the scleral tissue
surrounding the globe becomes more elastic achieved by methods
proposed in the present invention.
[0012] Therefore, one objective of the present invention is to
provide an apparatus and method to lower or eliminate the risks
factors causing AMD.
[0013] It is yet another objective of the present invention to use
a laser system with scanning device or fiber-coupled delivery unit
to control the ablation patterns, location, size and shapes on the
sciera tissue.
[0014] It is yet another objective of the present invention to
define the non-thermal lasers for efficient tissue ablation.
[0015] It is yet another objective of the present invention to
define the optimal laser parameters and the ablation patterns for
best clinical outcome for preventing AMD with minimum side
effects.
[0016] It is yet another objective of the present invention to
provide a new mechanism which supports the projected clinical
outcome of AMD prevention and the efficacy and long term efficacy
of this procedure. The mechanism presented in the present patent is
to remove portion of the sclera tissue which is filled in by
sub-conjunctiva tissue to increase the flexibility of the scleral
area and in turn lower the risk factors of vessel stiffening
causing AMD.
[0017] It is yet another objective of the present invention to use
a non-laser method to remove portion of the scleral tissue and
achieve the similar clinical outcome as that of laser methods, as
far as this removed scleral area can be filled in by the
sub-conjunctival tissue. These non-laser methods shall include, but
not limited to, physical blades or knife, electromagnetic wave such
as radio frequency wave, electrode device, bipolar device and
plasma assisted electrosurgical device.
[0018] The present invention described in great detail for the
prevention of AMD may be extended to other eye diseases including
glaucoma which require lowering of the intraocular pressure (IOP).
For the case of glaucoma, the laser and non-laser devices may be
used to remove sclera tissue in the area where Schlemm's channel is
located followed by a removal of a small portion of the iris
underlying this area Based on the elastic theory, the reduce of
rigidity of the sclera shall also IOP to prevent, delay or treat
glaucoma.
[0019] The invention having now been fully described, it should be
understood that it may be embodied in other specific forms or
variations without departing from the spirit or essential
characteristics of the present invention. Accordingly, the
embodiments described herein are to be considered to be
illustrative and not restrictive.
SUMMARY OF THE INVENTION
[0020] The preferred embodiments of the basic surgical lasers of
the present invention shall include (a) infrared (IR) lasers having
wavelengths range of about (1.4-3.2) microns including but not
limited to solid state lasers of Er:glass, Ho:YAG, Er:YAG, Er:YSGG,
infrared gas lasers, solid-state lasers converted by optical
parametric oscillation (OPO); (b) ultraviolet (UV) lasers having
wavelength range of about (190-355) nm, such as ArF (at 193 nm) and
XeCl (at 308 nm) excimer lasers, nitrogen laser (at 337 nm) and
harmonics of solid-state lasers using frequency up-conversions; (c)
semiconductor diode lasers at about 980 nm, (1.3-1.55) microns, and
(1.8-2.1) microns; (d) flash-lamp-pumped and diode-pumped solid
state lasers having wavelength range of about (190-355) nm and
(2.7-3 2) microns such as Er:YSGG, Er:YAG, Nd:YAG, Er:glass and
Ti:saphire laser and their harmonic generation; (e) short pulse
infrared lasers at (1.0-1.4) microns, with pulse duration of
between about 1.0 femtosecond and 10 nanoseconds.
[0021] It is yet another preferred embodiment is to couple the
basic lasers by a fiber and deliver the laser beam to the treated
area of the eye by a hand held piece which is further connected to
a fiber-tip at various shapes.
[0022] It is yet another preferred embodiment to focus the laser
beams into a desired spot size on the treated area of the eye.
Various ablation patterns may be generated manually via the
fiber-connected hand piece including multiple dotted rings and
radial line excisions outside the limbus.
[0023] It is yet another preferred embodiment to focus the laser
beams into a means of scanning device such that various ablation
patterns may be generated by controlling the scanning device. The
scanning devices shall include the use of a motorized reflection
mirror, refractive optics device or manually controlled translation
device.
[0024] It is yet another preferred embodiment is to remove, by any
methods either laser or non-laser, portion of the sclera tissue
which is filled in by sub-conjunctiva tissue to increase the
flexibility of the scleral area and in turn reduce the risk factors
of AMD and CNV.
[0025] The preferred embodiment for non-laser methods shall
include, but not limited to, physical blades or knife,
electromagnetic wave such as radio frequency wave, electrode
device, bipolar device and plasma assisted electrode device.
[0026] It is yet another preferred embodiment to open the
conjunctiva layer prior to the laser ablation of the under-layer of
the sciera tissue for a better control of the ablation depth and
for safety reasons. It is yet another preferred embodiment is that
the conjunctiva layer may be lifted to generate the "gap" for fiber
tip to insert into the gap and ablate the desired patterns
underneath and to avoid or minimize bleeding or infection.
[0027] Further preferred embodiments of the present invention will
become apparent from the description of the invention which
follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a schematics showing retinal development of
abnormal blood vessels (drusen) in the subretinal space which will
cause CNV.
[0029] FIG. 2 shows various layers of eye tissue outside limbus,
where the scleral tissue ablated by a laser is filled in by
sub-conjunctival (episclera) tissue after the conjunctiva flap is
replaced.
DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED
EMBODIMENTS
[0030] Referring to FIG. 1, The choroidal neovascularization (CNV)
1 is caused by the development of abnormal blood vessels (or
drusen) 2 in the sub-retinal space either between the
choriocapillaris 3 and the retinal pigment epithelum (RPE) 4 or
between the RPE and neurosonsory retine 5 which consists of
photoreceptor 6, bipolar cells 7 and optic nerve fibers 8. The
incoming light is shown as 9 and the sclear layer is shown as 10.
(From chapter 1, Physiology of the Eye, second ed. By I. Fatt and
B. Weissman, Butterworth-Heinemann, MA, 1992). The presence of the
abnormal vessels (or drusen), combined with the development of
subretinal transudates and hemorrhage, ultimately results in
irreparable damage to the overlying neurosensory retina (or
phtoaceptor) 6 and permanent loss of vision. Formation of these
drusen 2 is caused by the low flood flow and elevated pressure in
the choriocapillaris 3 which in turn is caused by the rigidity of
the sclera due to ageing.
[0031] FIG. 2 shows various layers of eye tissue outside limbus:
the conjunctiva 13, the sub-conjunctiva (or episclear) 14, the
sclear 15, the diary body 16 and the sclera area 17 removed/ablated
by a laser 12 The ablated area 17 having a depth about (50%-90%) of
the sclera total scleral thickness is filled in by the
sub-conjunctival tissue 14 after the conjunctiva flap is replaced.
This filled-in sub-conjunctiva in the area 17 is much more elastic
than the original scleral tissue 15, therefore the overall scleral
layer surrounding the eye globe will become more elastic. The
reduction the age-caused stiffness of the scleral tissue will lead
the increase of flood flow and decrease of choriocapillary pressure
and reduce the risk factors causing AMD or CNV.
[0032] Referring to FIG. 2, according to the present invention, the
preferred embodiments of the basic surgical laser 12 for the
prevention of AMD (or CNV) shall include: (a) infrared (IR) lasers
having wavelengths range of about (1.4-3.2) microns including but
not limited to solid state lasers of Er:glass, Ho:YAG, Er:YAG,
Er:YSGG, infrared gas lasers, solid-state lasers converted by
optical parametric oscillation (OPO); (b) ultraviolet (UV) lasers
having wavelength range of about (190-360) nm, such as ArF (at 193
nm) and XeCl (at 308 nm) excimer lasers, nitrogen laser (at 337 nm)
and solid-state lasers using harmonic generation from solid-state
lasers of Nd:YAG, Nd:YLF and alexandrite lasers frequency
conversions; (c) semiconductor diode lasers at about 980 nm,
(1.3-1.55) microns, and (1.8-2.1) microns; (d) diode-pumped solid
state lasers having wavelength range of about (190-355) nm and
(2.7-3.2) microns such as diode-pumped Er:YSGG, Er:YAG, Nd:YAG and
Er.glass; (e) short pulsed solid state laser at about (0.5-1.3)
microns with pulse width less than 10 nanoseconds.
[0033] According to one aspect of the present invention, the
preferable scanning laser energy per pulse on scleral surface is
about (1-40) mJ in IR lasers and about (0.1-5.0) mJ in UV lasers
and (0.001-0.1) mJ in ultra-short pulsed lasers. Focused spot size
of about (0.1-2.0) mm in diameter on the scleral surface is
proposed. The other preferred laser parameter of this invention is
the laser repetition rate range of about (1-100) Hz which will
provide reasonable surgical speed and minimum thermal effects. The
focused beam may be scanned over the scleral surface to ablate
various patterns either by a computer controlled scanner or
manually held fiber coupler consists of a hand piece and a fiber
tip.
[0034] The preferred patterns of this invention include a ring-spot
having at least one ring with at least 3 spots in each ring, and a
radial-pattern or a curved patterns having at least 3 radials or
curves or any non-specific shapes as far as they are symmetrically
in positions. The preferred area of the laser ablation is outside
the limbus such that the corneal refractive power will not be
affected by the procedure while the slceral is ablated. We also
propose that the ablation pattern on the scleral surface may be
generated either by an automatic scanning device or by manually
scan the fiber tip by a surgeon who hold the hand piece or other
scanning device suing refractive optics or rotating prisms. When a
fiber is used, the fiber tip may be penetrate into the sclera layer
without open the conjunctival layer and ablate the underlaying
tissue or open the conjunctival layer before the laser ablating the
sclera tissue. The fiber delivery unit may be operated in a
contact-mode or non-contact mode to ablate the sclera tissue.
[0035] The ablation depth of the sclera ciliary tissue shall be
about (60%-90%) of the total scleral thickness for safety reasons
and optimal clinical outcomes. Any other non-specific patterns
including curved lines, z-shape, t-shape lines around the area
outside the limbus should be within the scope of this patent.
[0036] The preferred embodiment without opening the conjunctiva
layer and inserting the fiber tip through the conjunctiva layer to
ablate the sclera tissue underneath is a less invasive procedure
than the one which opens the conjunctiva before the sclaral
ablation. To do this procedure, the conjunctiva layer may be lifted
to generate a "gap" for fiber tip to insert into this gap and
ablate the desired patterns underneath. Additional advantages of
this minimum invasive method is to avoid or minimize bleeding or
infection. We note that most of the bleeding is due to cutting of
the conjunctiva tissue rather than the laser ablation of the sciera
tissue.
[0037] It is yet another preferred embodiment is to remove, by
non-laser methods, portion of the sclera tissue which is filled in
by sub-conjunctiva tissue to increase the flexibility of the
scleral area. The preferred embodiment for these non-laser methods
shall include, but not limited to, physical blades or knife,
electromagnetic wave such as radio frequency wave, electrode
device, bipolar device and plasma assisted electrode device. The
electromagnetic wave generator is commercially available. However,
the parameters of the device such as its frequency, pulse duration
and repetition rate and the size of the electrode tip shall be
selected for efficient cutting (or ablation) with minimum thermal
damage to the tissue to be removed.
[0038] It is yet another preferred embodiment is to remove, by
laser or non-laser methods, portion of the sclera tissue for the
prevention, delaying or treatment of glaucoma by reducing the
intraocular pressure (IOP).
[0039] While the invention has been shown and described with
reference to the preferred embodiments thereof, it will be
understood by those skilled in the art that the foregoing and other
changes and variations in form and detail may be made therein
without departing from the spirit, scope and teaching of the
invention. Accordingly, threshold and apparatus, the ophthalmic
applications herein disclosed are to be considered merely as
illustrative and the invention is to be limited only as set forth
in the claims.
* * * * *